What were little things that told the ending of Paranormal Activity?

Toward the end of the movie, things start getting more intense in
the house, including Katie sleepwalking and staring at Micah for
long periods of time in his sleep. When the movie has about 10
minutes left, you see Katie being dragged out of bed by an unseen
force that is pulling her by her foot. She then wakes up and
screams for Micah as she is pulled out of the room and the door is
slammed. The audience is not aware of what is happening downstairs;
all we see is Micah being thrown at the camera, which Katie later
jumps at.